NASA built a new mega-rocket for the next lunar astronaut era, and it’s about to launch for the first time as soon as Tuesday.

The Space Launch System (SLS) is 17 years and an estimated $50 billion in the making. It’s designed to fly astronauts to the moon for the first time since 1972, when astronauts conducted the last moonwalk of the Apollo era.

NASA’s Space Launch System (SLS) rocket, with the Orion capsule atop, slowly makes its way down the crawlerway at the agency’s Kennedy Space Center in Florida on March 17, 2022.

The Space Launch System (SLS) at Kennedy Space Center in Florida on March 17, 2022.

NASA/Kim Shiflett

Now NASA is kicking off a new program, called Artemis, to build a space station orbiting the moon and set up a permanent human presence on the surface of the lunar south pole. Eventually, the agency wants to mine resources there to send astronauts to Mars.

This first mission, called Artemis I, is a test flight that will carry no astronauts. The rocket is set to scream through the Florida skies and push its Orion spaceship into a path around the moon and back. If that goes well, NASA aims to land astronauts on the lunar surface again in 2025.

NASA needs a powerful rocket to carry out such a long-distance mission. The current iteration of SLS, called Block 1, stands taller than the Statue of Liberty at 322 feet, about 30 stories.

To understand just how large that is, and just how much power it takes to fly to the moon, let’s compare it to other astronaut-flying rockets.

SLS is huge, but it’s small for a moon rocket

Let’s start small. The rocket that carried Jeff Bezos to the edge of space in July 2021, called New Shepard, stands about as tall as a five-story building. It doesn’t pack big enough engines, or large enough quantities of fuel, to push itself into Earth’s orbit.

jeff bezos inspects blue origin new shepard rocket booster

Blue Origin

Instead, New Shepard skims the edge of the atmosphere in the three minutes between when it stops climbing and when it starts falling. Then it descends back to Earth, for a total flight time of 11 minutes. That’s why it’s called a suborbital rocket.

new shepard reusable rocket launch 2016 blue origin

Blue Origin’s reusable New Shepard suborbital rocket launches toward space in 2016.

Blue Origin

Then there are orbital rockets, like Russia’s Soyuz and SpaceX’s Falcon 9, which generate enough thrust to push spaceships full of humans and cargo into orbit around the Earth, where they can dock at the International Space Station.

soyuz rocket laying on side atop wheeled vehicles with people in hardhats standing near

A Soyuz rocket arrive at the launch pad at the Baikonur Cosmodrome in Kazakhstan, September 28, 2009.

NASA/Bill Ingalls

Clocking in anywhere from 150 to 250 feet, these workhorses are probably what you’re picturing when you think of a standard rocket.

People look up at a SpaceX Falcon 9 rocket

People look up at a SpaceX Falcon 9 rocket at Cape Canaveral Air Force Station in Florida, October 7, 2012.


Lunar rockets like the Saturn V, which powered the Artemis program, are about another 100 feet taller. They need the extra thrust to push their spaceships past Earth’s orbit toward the moon.

saturn v 5 moon rocket apollo missions nasa 6864722_large

A Saturn V rocket launches an Apollo mission toward space.


SLS has white rocket boosters installed on the sides of its core stage, which burn solid fuel for extra firepower.

This close-up view shows the SLS rocket for Artemis I inside High Bay 3 of the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center in Florida on Sept. 20, 2021.

SLS in the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida on September 20, 2021.

NASA/Frank Michaux

Right now, SLS is smaller than its past and future lunar-grade counterparts. But future iterations of the rocket are expected to tower 365 feet.

two people stand on a platform halfway up a giant rocket

Technicians stack the SLS core stage at NASA’s Kennedy Space Center in Florida on June 12, 2021.

NASA/Cory Huston

If Artemis I goes well, the next SLS mission will send an Orion spaceship around the moon with astronauts on board. The following mission, according to NASA’s plan, will see Orion dock to a SpaceX Starship in lunar orbit. Two astronauts will board the new vessel, and Starship will land them on the moon’s south pole.

elon musk tiny in front of towering starship super heavy rocket skitch

Elon Musk stands before a Starship prototype stacked atop a Super Heavy booster prototype in Boca Chica, Texas on February 10, 2022.


Starship and its Super Heavy booster are still in development and testing at SpaceX facilities in Boca Chica, Texas. It’s unclear when they will launch to orbit for the first time — a critical test flight before the rocket can fly humans or land on the moon.

black starship rocket stacked atop silver super heavy boost on flat texas plain against blue skies

SpaceX’s Starship stacked atop its Super Heavy booster at the company’s facility near Boca Chica, Texas on February 10, 2022.

Jim Watson/AFP via Getty Images

Starship-Super Heavy is slated to be the largest rocket ever built.